Publication 700-AT001A-EN-E June 2002
1-2
Basic Concepts of SSRs
Configuration of SSRs
Representative Example of Switching AC Loads
Isolated input circuit
Input
terminals
Input circuit
Electr
ical isolation
Dr
iv
e circuit
Output circuit
Output
terminals
SSR circuit
configuration
Semiconductor
output element
Input
terminals
and tr
ansistor
Diode
, LED
, resistor
,
Phototr
iac coupler
Photocoupler
Diode
, capacitor
, resistor
,
and v
a
ristor
Resistor
, capacitor
,
and v
a
ristor
po
w
e
r
tr
ansistor
, th
yr
istor
,
Output
terminals
SSR
Component
Configuration
Power transistor (for DC loads)
Thyristor (for AC loads)
Triac (for AC loads)
and tr
iac
Input
Output
Light
Phototriac
coupler
Triac
No
operation
noise
Long
life
SSRs are
SPST-NO
Input circuit
Zero cross function
T
rigger circuit
High-speed,
high-frequency
switching
Minimal
noise
generation
Heat
dissipation
is required
A surge
voltage
may
damage
the
elements.
Leakage
current
Drive
circuit
Snubber
circuit